Cosmetic compositions containing multi-block ionizable polysiloxane/polyurethane and/or polyurea polycondensates in solution, and uses thereof

ABSTRACT

Cosmetic compositions based on multiblock ionizable polycondensates, and uses thereof The invention relates to novel cosmetic or dermatological compositions, characterized in that they comprise, in a cosmetically acceptable support, at least one solution or one emulsion of at least one multiblock polycondensate whose chain consists of the repetition of at least one polysiloxane block and of at least one polyurethane and/or polyurea block; the said polyurethane and/or polyurea block also including ionizable groups and the said polycondensate being dissolved in an aqueous, organic or aqueous-organic solvent system. These compositions may be used in particular in the cosmetic field of hair care, make-up or skincare.

This application is a 371 of PCT/FR96/01976 filed Dec. 10, 1996.

The present invention relates to novel cosmetic or dermatologicalcompositions with film-forming properties, containing solutions ofspecific multiblock ionizable polycondensates, as well as to variouspossible uses thereof, in particular in the field of cosmetic (i.e.topical) treatment of the skin, the hair, the nails and other keratinsubstances.

It is common practice in cosmetic formulations, in particular in hairproducts (shampoos, conditioners, styling or treating lotions or gels,lacquers or lotions for shaping, setting, fixing, and the like the hair)or in make-up products (such as, for example, nail varnish, mascaras,eyeliners and the like), to use a variable proportion, depending on thenature and destination of the formulation, of at least one film-formingsubstance which makes it possible, or is intended to give the support onwhich it is applied (that is to say, here, one of the surface parts ofthe body, such as head hair, eyelashes, body hair, skin, nails, etc.)certain improved characteristics. Thus, for example, in the specificcase of treating a head of hair, more staying power and more softness ofthe hair are especially sought by this technique, whereas in the morespecific case of the nails, it is mainly sought to obtain a protective,shiny and hard film which adheres fully to the nails.

In order to be satisfactory in cosmetic applications, a film-formingresin needs to have certain restricting characteristics or properties,among which mention may be made more particularly, in a non-limitingmanner, firstly, of a very good affinity/compatibility/harmlessness withrespect to various keratin substances (skin, hair and the like), next,good film-forming properties relative to these substances (quality anduniformity of the film deposited), and, lastly, good remanenceproperties (adhesiveness, solidity), that is to say that it must bedifficult to remove from its support by simple washing with water orusing detergents (shampoos) for example. In the case of nail varnishes,the film must also have good mechanical abrasion strength. In general,it will be noted that it is often difficult in practice to find afilm-forming substance which is capable of effectively satisfyingseveral, or all, of the various cosmetic applications which may beenvisaged for this substance (problem of the acceptable compromise).

In certain respects, the film-forming substances known to date, and inparticular those mentioned above, are poorly suitable for obtainingcompositions having good cosmetic properties, on account, in particular,of an appreciable lack of remanence, in particular of water-resistance.

Another problem lies in the fact that the films thus obtained, inparticular in the context of applications of mascara or hair type, arenot sufficiently shiny. This sheen is also only poorly remanent, that isto say that it disappears quickly under the action of external agents(highly water-sensitive in particular).

However, the sheen, as well as the remanence of this sheen, nowadaysconstitutes a particularly desired property in the field of cosmetics.

It is thus seen that there is currently a strong need in the state ofthe art to have available cumulating film-forming compositions, for avaried field of possible applications (hair, eyelashes, skin, nails,etc.), all the advantages generally desired or desirable in cosmetics,namely, in particular, harmlessness towards keratin substances, ease ofapplication and of use, production of thin and uniform protectivedeposits, remanence of the adhesive properties, provision and remanenceof sheen properties, provision of softness and lubrication, rigidity andabrasion-resistance.

In order to meet this need, it has been proposed to use mixtures ofpolymers which make it possible to combine all of these properties, inparticular mixtures of polyorganosiloxanes (silicones) with non-siliconepolymers. The reason for this is that it is known that silicones provideexcellent surface properties, leading to good lubrication, good sheenand a soft feel without providing fatty substances. These polymers donot have good mechanical properties for ensuring good film-formation;they thus need to be combined with other polymers which providemechanical properties. Polyorganopolysiloxanes, in particularpolydimethylsiloxanes, are incompatible with most of the non-siliconepolymers which provide mechanical properties.

To overcome these drawbacks, French patent No. 2,708,199 teaches thepossibility of using a stable aqueous suspension consisting of fine,solid, generally spherical particles of polysiloxane/polyurethane and/orpolyurea multiblock ionic polycondensate, these particles having beenobtained by placing the said polycondensate in the pre-synthesized statein dispersion in a suitable aqueous phase. This type of dispersion ofwater-insoluble polymer is called a “pseudo-latex”. However, thesepseudo-latices have certain drawbacks.

These ionizable polycondensates in aqueous suspension do not make itpossible to potentiate the desired conjugation of the propertiesprovided, on the one hand, by the silicone segments and, on the otherhand, by the polyurethane and/or polyurea segments. This addivity of theproperties can only be optimized if good phase separation between thesilicone segments and the polyurethane and/or polyurea segments takesplace during drying, such that there is, on the one hand, in the solidstate, an actual stratification of the silicone segments at the surfaceof the matrix of the deposit consisting of the polyurethane and/orpolyurea segments—it is, in fact, at the interface of this matrix withair that the specific properties of the silicones will bemanifested—and, on the other hand, such that the silicone segments areassembled inside the matrix of the deposit in the form of a dispersedphase.

It is very difficult to obtain, with pseudo-latices consisting ofpolysiloxane/polyurethane and/or polyurea ionizable polycondensates,good phase separation leading to this stratification of the siliconesegments at the surface of the deposit and the formation of a siliconephase inside the deposit, and more particularly when the lengths of thepolysiloxane and/or polyurethane and/or polyurea sequences are short.The result of this is that the addivity of the properties as definedabove which is obtained by these pseudo-latices still remainsinsufficient.

Thus, after considerable research conducted in this matter, theApplicant has now found, surprisingly and unexpectedly, that it ispossible to improve this phase separation substantially and consequentlyto potentiate the addivity of the surface properties provided by thesilicones and the mechanical and/or adhesion properties provided by thepolyurethanes and/or polyureas, by using solutions or emulsions of thesesame polysiloxane/polyurethane and/or polyurea multiblock ionizablepolycondensates dissolved in an aqueous, organic or aqueous-organicsolvent system.

Furthermore, the polycondensates in solution of the invention exhibitbetter remanence of the deposit to the action of water or of surfactantsolutions (shampoos) than pseudo-latices consisting of the samepolycondensates.

In accordance with the present invention, novel cosmetic compositionsare therefore now proposed, which are characterized in that theycomprise, in a cosmetically acceptable support, at least one solution orone emulsion of at least one multiblock polycondensate whose chainconsists of the repetition of at least one polysiloxane block and of atleast one polyurethane and/or polyurea block; the said polyurethaneand/or polyurea block also including ionizable groups and the saidpolycondensate being dissolved in an aqueous, organic or aqueous-organicsolvent system.

The expression “ionizable group” is understood to refer to any groupwhich may be ionized by a neutralization reaction of an acidic or basicfunction borne by the said group, or a quaternization reaction of atertiary amine function borne by the said group, and which may thus forman anionic, cationic, amphoteric or zwitterionic group.

The polycondensates of the invention are essentially prepared accordingto a two-step process. The first step consists of a standardpolycondensation reaction between (i) a polysiloxane (or silicone)polymer having a hydroxyl function or an amine function at the ends ofits chain (i.e. an α,ω-dihydroxypoly-siloxane, or anα,ω-diaminopolysiloxane, or an α,ω-aminohydroxy- orhydroxyamino-polysiloxane), and (ii) a diisocyanate (present instoichiometric amount, or in stoichiometric excess, that is to say atmore than 2 mol per mole of silicone), whereby a novel silicone isobtained, this time having an isocyanate function at each of its chainends; then, in a second step, the chains of the polycondensate obtainedabove are coupled by means of a coupling agent (in variable amountchosen as a function of the desired final chain length) chosen fromdiols and/or diamines and/or alcoholamines, so as finally to obtain anovel polycondensate of longer chain length.

The reactions used in the first step thus lead to a polysiloxane havingat its chain ends, besides the isocyanate functions mentioned above,urethane and/or urea units, according to the standard mechanisms for acondensation reaction carried out between (i) an isocyanate function, asborne by the starting diisocyanate, and (ii) an alcohol function(creation of a urethane unit in this case) or of an amine function(formation of a urea function in this case), as borne by the startingpolysiloxane, namely:

 (polysiloxane)-OH+O═C═N—R—N═C═O→-(polysiloxane)-O—CO—NH—R—N═C═O(diisocyanate)

and/or

(polysiloxane)-NH2+O═C═N—R—N═C═O→-(polysiloxane)-NH—CO—NH—R—N═C═O

The polycondensates obtained after this first step may thus effectivelybe defined by the general formula (1) below:

O═C═N—R—NH—CO═X¹-(polysiloxane)-X¹—O—NH—R—N═C═O  (1)

in which X¹ may thus represent, separately or in combination, —O— or—NH—.

In the second step, the alcohol and/or amine functions of the coupler(which coupler may conveniently be symbolized here by OH—B—OH, orNH₂—B—NH₂ or alternatively NH₂—B—OH) then react, according to the samemechanisms as those shown for the first step, either with the isocyanatefunctions borne at the end of the chain by the polysiloxanepolycondensate of formula (1) above, or with isocyanate functions borneby free diisocyanate, when the latter has been introduced instoichiometric excess during the first step, thus giving rise in thechain (longer) of the new polycondensate obtained to a sequence ofurethane and/or urea units, that is to say polyurethane and/or polyureatype blocks which may be symbolized by formula (2):

which X² represents —O— or —NH—, and x is a value correspondingsubstantially to the number of moles of coupler used in the reaction.

As indicated above, a polycondensate consisting of the repetition ofpolysiloxane blocks (corresponding simply to the starting polysiloxane,and as appears in formula (1)) and polyurethane and/or polyurea blocks(formula (2)) is thus finally obtained.

According to an extremely important aspect of the invention, thecouplers (that is to say, effectively, the radical B) bear ionizablegroups, that is to say groups which, and respectively, when subjected tothe action of a base, give anionic groups (this is the case, forexample, of carboxyl groups) and when subjected to the action of an acidor quaternization, give cationic groups (the case, for example, of atertiary amine). Neutralization of the anionizable groups (orcationizable groups respectively) with the base (or the acidrespectively) may be carried out partially or completely, depending onthe amounts of neutralizing agents used.

However, other characteristics, aspects and advantages of the inventionwill now become more apparent on reading the detailed and fulldescription which follows, as well as the various concrete, but in noway limiting, examples intended to illustrate it.

As indicated above, the chain of the ionizable polycondensate used inthe context of the present invention is essentially characterized inthat it consists of the repetition (or alternation) of at least onepolysiloxane type block and of at least one polyurethane and/or polyureatype block, the said polyurethane and/or polyurea blocks containingionizable groups. Other blocks of different chemical nature may be inthe chain of the polycondensate. Mention may be made, for example, ofpolyether blocks such as polyoxyethylene, polyoxypropylene,polytetramethylene oxide and/or polyester blocks such as poly(ethyleneglycol adipate), poly(neopentyl glycol sebacate) or poly(ethylene glycolterephthalate).

The repetition of the above blocks may be of random type, but it ispreferably of regularly alternating type. In addition, the numericalratio between the polyurethane and/or polyurea type blocks and thepolysiloxane type blocks is generally between 1 and 10, preferablybetween 1 and 3.

The molecular weights of the polysiloxane-polyurethane/polyureapolycondensates may vary within a wide range, in particular between 2000and 500,000, but preferably between 3000 and 250,000.

Preferably, the polysiloxane block corresponds to the general formula(I) below:

which: in

P is a polysiloxane segment,

X¹ represents, separately or in combination, —O— or —NH—,

and R (which is none other than the diisocyanate unit as mentionedabove) is a divalent radical chosen from alkylene radicals of aromatic,aliphatic or cycloaliphatic type.

Preferably, the polysiloxane segment P corresponds to the generalformula (I′) below:

which the Radicals R¹, which may be identical or different, are chosen,on the one hand, from monovalent C₁-C₂₀ hydrocarbon radicals which arefree or substantially free of ethylenic unsaturations, and, on the otherhand, aromatic radicals, Y represents a divalent hydrocarbon radical andz is an integer such that the average molecular weight of thepolysiloxane segment is between 300 and 10,000.

Preferably, Y is a divalent radical chosen from alkylene radicals offormula —(CH₂)_(a)—, in which a represents an integer which may bebetween 1 and 10.

As radicals R¹ which are suitable in the context of the invention,mention may be made more particularly of alkyl radicals and, inparticular, methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl,octyl, decyl, dodecyl and octadecyl radicals, cycloalkyl radicals, inparticular the cyclohexyl radical, aryl radicals, in particular phenyland naphthyl, arylalkyl radicals, in particular benzyl and phenylethyl,and tolyl and xylyl radicals. It will be noted that, according to theinvention, it is important for the polysiloxane segment to be free, orsubstantially free, of units of the Si—H or Si—R¹ type in which R¹represents a hydrocarbon radical having ethylenic unsaturations, so asto avoid any untimely crosslinking of the polycondensate with itself.

According to a particularly preferred embodiment of the presentinvention, the polysiloxane segment P present in the polycondensatescorresponds to formula (I″) below:

in which a and z are values as defined above.

As regards, now, the polyurethane and/or polyurea blocks which form apart of the polycondensates used in the context of the invention, thesepreferably correspond to the general formula (II) below:

which: in

X² represents, separately or in combination, —O— or —NH—,

R (which, as above for formula (I), is none other than the diisocyanateunit used to carry out the condensation reaction) is as defined abovefor the blocks of formula (I),

x (which, as indicated above in the description correspondssubstantially to the number of moles of couplers used in the process forsynthesizing the polycondensate) is an integer which may range from 1 to10 and preferably from 1 to 3,

and B (which is none other than the unit provided by the coupler asmentioned above) is a divalent hydrocarbon radical bearing a positive ornegative ionic charge.

As radicals B bearing anionic groups (i.e. negative charges), mentionmay be made more particularly of those which bear groups having one ormore carboxylic function(s) and/or one or more sulphonic functions, thesaid carboxylic and/or sulphonic functions being in free form or beingpartially or totally neutralized with an inorganic or organic base, aswill be explained in greater detail hereinbelow.

Thus, among the divalent radicals B bearing carboxylic or sulphonicfunctions which are particularly suitable in the context of the presentinvention, mention may be made of those of formula (III):

which R² represents a linear or branched C₁-C₃ alkyl radical, Zrepresents a carboxylic acid (—COOH) function or sulphonic acid (—SO₃H)function or a salt of the said acidic functions (carboxylate andsulphonate functions, respectively), and p and q, which may be identicalor different, are integers between 1 and 5, and those of formula (III′):

in which z has the above meaning.

As radicals B bearing cationic groups (i.e. positive charges), mentionmay be made more particularly of those which bear groups of tertiaryamine type, the said tertiary amines being either non-neutralized orpartly or totally neutralized (presence of —NH⁺— units) or quaternized,as will be explained in greater detail hereinbelow.

Thus, among the divalent radicals B bearing cationizable tertiary aminefunctions which are particularly suitable in the context of the presentinvention, mention may be made of those of formula:

which R³ represents a linear or branched C₁-C₄ alkyl radical and r and sare both integers, which may be identical or different, which may bebetween 1 and 10.

In neutralized or quaternized form, the above radicals B then become:

in which formula R³ has the above meaning, and R⁴ represents eitherhydrogen (neutralization) or a linear or branched C₁-C₁₀ alkyl radicalor an aromatic ring (quaternization).

According to the invention, the degrees of neutralization of theanionizable or cationizable functions may be between 0 and 100%,preferably between 10 and 100%.

The radicals B of the coupler bearing an ionic charge may be used aloneor as a mixture with other radicals B′ originating from couplers notbearing an ionizable group.

Lastly, as regards the radicals R more particularly preferred accordingto the present invention, which fall within the scope of the definitionof the blocks of formulae (I) and (II) given above, mention may be madeof those of formulae:

which b is an integer between 0 and 3 and c is an integer between 1 and20, preferably between 2 and 12.

Among the particularly preferred divalent radicals R which fall withinthe scope of the above formulae, mention may be made of hexamethylene,4,4′-biphenylenemethane, 2,4- and/or 2,6-tolylene, 1,5-naphthylene,p-phenylene and methylene-4,4-bis-cyclohexyl radicals and the divalentradical derived from isophorone.

The process for synthesizing the polycondensates used in the context ofthe present invention will now be developed in slightly more detail. Inthese main points, this process corresponds to that already indicated atthe start of the description.

An α,ω-dihydroxy and/or diamino and/or amino-hydroxy and/orhydroxyaminopolysiloxane corresponding to the following general formula:

X³—P—X³

in which P has the meaning given above (polysiloxane segment) and X³represents, in combination or separately, —OH or —NH₂, is reacted, in anorganic solvent, with a stoichiometric excess of a diisocyanate offormula:

O═C═N—R—N═C═O

in which R has the meaning given above, followed by coupling the chainsof the polycondensate obtained above with at least one diol and/or adiamine and/or an aminoalcohol corresponding to the formula:

X⁴—B—X⁴

in which B has the meaning given above and X⁴ represents —OH or —NH₂, ata temperature of between 40 and 100° C., in the presence of a tin saltas catalyst. This diol and/or this diamine X⁴—B—X⁴ may be used alone oras a mixture with one or more diols or diamines or amino alcohols notcontaining ionizable groups, for example 1,4-butanediol.

The organic solvent used in these steps is preferably chosen from thegroup consisting of acetone, methyl ethyl ketone, tetrahydrofuran and1,2-dichloroethane, the solvents being inert towards isocyanate groups.

The tin salt is, itself, preferably chosen from 2-ethyltin hexanoate anddibutyltin dilaurate.

In the context of carrying out the above process, the diisocyanateswhich are particularly preferred are chosen, alone or as mixtures, fromdiphenylmethane 4,4′-diisocyanate and methylene-4,4′-dicyclohexyldiisocyanate, and the couplers which are particularly preferred arechosen, alone or as mixtures, from dimethylolpropionic acid,N-methyldiethanolamine, 1,3-diaminopropane and ethanolamine, it beingunderstood that the possibility of mixing acidic coupler/amino coupleris excluded.

The polysiloxane-polyurethane/polyurea polycondensate thus obtained maythen optionally be purified, for example by precipitation in a non-polarsolvent such as cyclohexane.

In accordance with the invention, this optionally purifiedpolycondensate is then either used in its natural state or neutralizedusing a suitable neutralizing agent which may be either an inorganic ororganic base when the radical B as defined above bears anionizablefunctions such as, for example, carboxylic and/or sulphonic acidfunctions, or an inorganic or organic acid when the said radical B bearscationizable functions such as, for example, tertiary amine functions;or quaternized using an alkyl halide, an acidic salt bearing a labilehalogen or a sultone (for example propane sultone) when the said radicalB bears tertiary amine functions.

According to the invention, the degree of neutralization may range from0% to 100%, preferably from 10% to 100%.

It goes without saying that the nature of the neutralizing agent whichwill be suitable for use in neutralizing thepolysiloxane-polyurethane/polyurea polycondensate will depend on thenature of the ionizable functions borne by this polycondensate.

When the said polycondensate contains an anionizable function such as,for example, a carboxylic or sulphonic acid function, the neutralizingagent may be an inorganic base such as sodium hydroxide, potassiumhydroxide or aqueous ammonia, or an organic base such as an aminoalcohol chosen in particular from 2-amino-2-methyl-1-propanol (AMP),triethanolamine, triisopropanolamine (TIPA), monoethanolamine,diethanolamine, tris[(2-hydroxy)-1-propyl]amine,2-amino-2-methyl-1,3-propanediol (AMPD) and2-amino-2-hydroxymethyl-1,3-propanediol, or alternatively a diamine suchas lysine.

When the polycondensate contains a cationizable function of the tertiaryamine type, the neutralizing agent may be an inorganic acid such ashydrochloric acid or an organic acid such as lactic acid, glycolic acidor mandelic acid. The neutralizing agent may also be an agent whichquaternizes the tertiary amine function, such as, for example, alkylhalides and in particular methyl iodide or ethyl bromide. It may also bean acid salt bearing a labile halogen or a cyclic sulphonic acid ester.

A solution or an organic solvent-in-water emulsion of the polycondensatein accordance with the invention is then prepared by incorporating itinto an organic, aqueous or aqueous-organic solvent system.

The organic solvents for the polycondensates of the invention which areused according to the invention are preferably chosen from acetone,methyl ethyl ketone, methyl acetate, butyl acetate, ethyl acetate,isopropanol, ethanol, dimethoxyethane, diethoxyethane, an ethyleneglycol or a propylene glycol ester, an ethylene glycol or a propyleneglycol ether, or an ethylene glycol or a propylene glycol ester ether,and mixtures thereof.

Depending on the type of application chosen, it is possible to use,among these solvents for the polycondensates of the invention, a solventor a mixture of solvents which are miscible with water, one of which(which serves as diluent) evaporates before water so as to allow thepolymer to be dissolved in a solvent throughout the drying of theformulation applied to the keratin substance treated. Among thewater-miscible solvents, mention may be made of dimethoxyethane and adimethoxyethane/diethoxyethane mixture. If the formulation envisagedrequires the presence of water for the given application, the organicsolution of the polymer may, in this case, be diluted in water in orderto form an organic solvent-in-water emulsion. This emulsion may beself-stabilized by the ionic charges borne by the polycondensate, whichplace themselves at the interface with the water, or alternativelystabilized, if necessary, by stabilizers such as surfactants or gellingagents that are present in the aqueous phase.

It is also possible to choose a solvent or a mixture of solvents, forthe polycondensates of the invention, that are immiscible with water,such as diethoxyethane. If the formulation envisaged requires thepresence of water for the given application, the organic solution of thepolymer may, in this case, be dispersed in water in order to form anorganic solvent-in-water emulsion. This emulsion may be self-stabilizedby the ionic charges borne by the polycondensate, which place themselvesat the interface with the water, or stabilized, if necessary, bystabilizers such as surfactants or gelling agents present in the aqueousphase. In this case, the organic solvent or one of the organic solventsused to dissolve the polycondensate preferably has a boiling pointhigher than that of water. Diethyoxyethane may be used in particular.

A particularly preferred form of solvent system for the polycondensatesof the invention consists in using a mixture of solvents of differentpolarities comprising at least one solvent (A) known as a “global”solvent for the polycondensate (for the polysiloxane blocks and thepolyurethane and/or polyurea blocks) and at least one solvent (B) whichis less than polar (A) and which will more specifically dissolve thepolysiloxane blocks. In order to promote the stratification of thepolysiloxane blocks on the deposition matrix, a solvent (B) whose rateof evaporation is slower than (A) will preferably be chosen.

Among the global solvents (A), mention may be made of acetone, methylethyl ketone, methyl acetate, butyl acetate, ethyl acetate, isopropanol,ethanol, dimethoxyethane, diethoxyethane, an ethylene glycol or apropylene glycol ester, an ethylene glycol or a propylene glycol ether,or an ethylene glycol or a propylene glycol ester ether, and mixturesthereof.

Among the solvents (B), mention may be made of hydrocarbons, inparticular branched hydrocarbons such as isoparaffins, isodecane andcyclic silicones of the type D₄, D₅ or D₆.

The neutralization may be performed in situ in the solution of thepolysiloxane-polyurethane/polyurea polycondensate in the solvent systemby adding the determined amount of neutralizing agent.

As indicated above, the cosmetic compositions according to theinvention, which thus contain, in a cosmetically acceptable support,polycondensates as defined above, have, for applications as varied asthose encountered, for example, in the field of hair care or make-up oralternatively skincare, or in any other cosmetic field in which the useof a film-forming substance is desirable or sought, entirely noteworthyproperties, in particular as regards their sheen and film-formingproperties, their ability to retain these properties over time in theface of the action of external agents (remanence) and also as regardstheir properties of softness, lubrication and abrasion-resistance.

Among the applications preferably targeted by the present invention, andthe various beneficial effects obtained in these applications, mentionmay be made more particularly of:

the field of hair products (washing, care or beauty of the hair), wherethe compositions according to the invention, in particular in aerosol,mousse, shampoo, conditioner, styling or treating lotion or gel, hairshaping or hair setting lacquer or lotion or alternatively fixing form,give the hair sheen, softness, ease of styling (phenomenon of“individualization” of the hair when the composition is applied), abetter feel and remanence (that is to say long-lasting maintenance, evenunder the action of external agents) of these properties.

The field of make-up products, in particular for making up the nails andthe eyelashes, where the compositions according to the invention, innail varnish, mascara or eyeliner form, for example, afford, in the caseof making up the eyelashes, the same advantages as those mentioned abovefor treating the hair, and, in the case of nail varnishes (where thecompositions may be used as sole film-forming agents or as film-formingadditive), sheen, better wettability of the nail, remanence of the filmand of its sheen on washing, better abrasion-resistance (provision of asliding effect by lubrication of the surfaces) and better rigidity.

In the field of skincare products (creams, milks, lotions, masks, sera,antisun products), where the compositions according to the inventionmore particularly afford sheen, better wettability and resistance towashing with water (antisun products).

The proportion of polycondensate in the cosmetic compositions (excludingnail varnishes) is generally between 0.5 and 50% and preferably between1 and 20% by weight relative to the total weight of the composition. Inthe case of nail varnishes, this proportion may be up to 30% by weight.

The compositions may also, obviously, contain various adjuvants intendedto make them acceptable in a particular cosmetic application.

The compositions according to the invention may contain UV-A or LTW-B orbroad-band sunscreens and may thus be used as antisun products.

The compositions according to the invention may moreover containconventional cosmetic additives chosen from fatty substances, organicsolvents, silicones, thickeners, softeners, antifoaming agents,moisturizers, wetting agents, treating agents (agents for combating hairloss, antidandruff agents, etc.), anionic, nonionic or amphotericpolymers or mixtures thereof, antiperspirants, basifying agents, dyes,pigments, fragrances, preserving agents and propellants when thecompositions are in aerosol form.

More precisely, an oil or a wax or mixtures thereof, fatty acids, fattyalcohols, fatty acid esters such as triglycerides of C₆-C₁₈ fatty acids,petroleum jelly, paraffin, lanolin or hydrogenated or acetylated lanolinmay be used as fatty substance.

Among the oils, mention may be made of mineral, animal, plant orsynthetic oils and in particular liquid petroleum jelly, liquidparaffin, castor oil, jojoba oil or sesame oil, as well as silicone oilsand gums and isoparaffins.

Among the animal, fossil, plant, mineral or synthetic waxes, mention maybe made in particular of beeswax, carob wax, candelilla wax, ozocerite,micro-crystalline waxes and silicone waxes and resins.

Among the thickeners, mention may be made of:

modified celluloses such as hydroxyethylcellulose, methylcellulose,hydroxypropylcellulose and carboxy-methylcellulose. Among these, mentionmay be made in particular of the gums sold under the name “Cellosize QP44001H” by the company Amercol,

carob gum, guar gum, quaternized guar gum, sold under the name “JaguarC-13-S” by the company Meyhall, hydroxypropyl guar gum, xanthan gum,

crosslinked polyacrylic acids such as the “Carbopols” from the companyGoodrich,

the polyglyceryl (meth)acrylate polymers sold under the names “Hispagel”or “Lubragel” by the companies Hispano Quimica and Guardian,

polyvinylpyrrolidone,

polyvinyl alcohol,

crosslinked acrylamide polymers and copolymers, such as those sold underthe names “PAS 5161” or “Bozepol C” by the company Hoechst, “Sepigel305” by the company Seppic or “Salcare SC95” by the company AlliedColloid, or alternatively

crosslinked homopolymers of methacrylolyloxy-ethyltrimethylammoniumchloride, sold under the name “Salcare SC95” by the company AlliedColloid.

Several examples of the preparation of polysiloxane-polyurethanepolycondensates and of their solutions or emulsions and of cosmeticcompositions containing them will now be given by way of illustration ofthe invention.

The syntheses leading to the polysiloxane-polyurethane multiblockpolycondensates were carried out starting with prepolymers of theα,ω-hydroxyorgano-functional polydimethylsiloxane type (commercialproducts sold by the company Goldschmidt under the names Tegomer H-Si2111 and Tegomer H-Si 2311) of structure:

and also having the characteristics collated in the table below:

Functional groups Primary hydroxyl groups Commercial name Tegomer H-Si2111 Tegomer H-Si 2311 Functionality 2 2 Number of units z about 10about 30 Hydroxyl number 120 (±10) 45 (±5) (mg KOH/g) Viscosity at 25°C. (cP) 85 (±10) 115 (±15) Number-average 700 2200 molecular weight (Mn)

These two commercial products will be referred to hereinbelow forconvenience as SIL 700 and SIL 2200 (name based on their respectivemolecular weights).

EXAMPLE 1

In this example, an anionizable polysiloxane-polyurethane polycondensatewas prepared, of theoretical structure:

in which R represents:

and corresponding to the reaction between:

1 mol of SIL 700 (polysiloxane prepolymer)

2 mol of 4,4′-diphenylmethane diisocyanate (referred to hereinbelow asMDI)

and 1 mol of dimethylolpropionic acid (coupler, referred to hereinbelowas DMPA), these values being relative to 1 mol of SIL 700.

50 g of MDI and 50 g of tetrahydrofuran (THF) are introduced, under astream of nitrogen, into a cylindrical reactor fitted with a centralstirrer of the anchor-paddle type, a thermometer, a condenser and aninlet for bubbling nitrogen through, and mounted with a dropping funnel.The mixture is dissolved with stirring and at room temperature.

Simultaneously, 70 g of SIL 700 are dissolved in 70 g of THF and thesolution thus obtained is poured into the dropping funnel located abovethe reactor.

This solution of SIL 700 is then introduced, with stirring and under astream of nitrogren, into the reactor containing the solution of MDI,while maintaining the temperature of the reaction medium at 50° C. byexternal heating.

The introduction of the SIL 700 solution lasts 1 h 30 and thetemperature of the reaction medium is maintained at 50° C. throughoutthe introduction.

After the solution has been introduced, the reaction leads to thequantitative formation of a polysiloxane prepolymer containingα,ω-diisocyanate ends.

A solution of DMPA obtained by dissolving 13.4 g of DMPA in 400 g of THFis then introduced (introduction time: 30 min) into the reactorcontaining the above prepolymer, still with stirring, bubbling withnitrogen and maintenance of the temperature at 50° C. At the start ofthe introduction, 0.15 g of dibutyltin dilaurate which serves ascatalyst is also introduced into the reaction medium. The whole is thenleft to react for 10 h, with stirring and at 50° C.

The end of the reaction may be monitored by checking, by infraredanalysis, the absence of —N═C═O absorption bands at 2270 cm⁻¹. Ifneeded, ethanol may also be added to the reaction medium in order toquench the reaction and totally consume the —N═C═O groups that are stillavailable; in this case, it is possible, for example, to add about 10 mlof ethanol and leave the whole to react for a further 4 h at 50° C.

At the end of the reaction, an organic (THF) solution of the desiredpolycondensate is obtained, which is then recovered and purified byprecipitation of the said solution in 5 l of an equi-volume (50/50)petroleum ether/ethyl ether mixture. The recovery yield is 90% by weightafter drying.

The acid number of the polycondensate obtained is 46 (theoretical: 42).

Its number-average molecular weight is 5000.

The polymer obtained is soluble in solvents such as dimethoxyethane,ethanol, isododecane and ethyl acetate.

EXAMPLE 2

An anionizable polysiloxane-polyurethane polycondensate of the sametheoretical structure as that of Example 1, but this time obtained fromthe polysiloxane prepolymer SIL 2200, is prepared here.

The procedure followed is thus identical to that of Example 1, but theamounts of reactants used are this time as follows:

80 g of SIL 2200 dissolved in 80 g of THF

18.2 g of MDI dissolved in 20 g of THF

4.9 g of DMPA dissolved in 200 g of THF

0.1 g of dibutyltin dilaurate in order, here also, to abide by theproportions 1 mol of SIL 2200: 2 mol of MDI: 1 mol of DMPA.

In addition, the recovery and purification of the desired finalpolycondensate takes place this time more simply by precipitation of theorganic solution containing it in 5 l of deionized water.

The recovery yield is, in this case, 92% by weight.

The acid number of the polycondensate obtained is 21.7 (theoretical:19.8).

Its number-average molecular weight is 6300.

The polymer obtained is soluble in solvents such as dimethoxyethane,ethanol, isododecane and ethyl acetate.

EXAMPLE 3

In this example, a cationizable polysiloxane-polyurethane polycondensatewas prepared, of theoretical structure:

in which R represents:

and corresponding to the reaction between:

1 mol of SIL 700

2 mol of MDI

1 mol of N-methyldiethanolamine (coupler, referred to hereinbelow asMEA) these values being relative to 1 mol of SIL 700.

50 g of MDI and 50 g of THF are introduced, under a stream of nitrogen,into the same reactor as that of Example 1, equipped in the same way.Dissolution of the mixture takes place with stirring and at roomtemperature.

In parallel, 70 g of SIL 700 are dissolved in 70 g of THF and thesolution thus obtained is poured into the dropping funnel located abovethe reactor.

This solution of SIL 700 is then introduced, with stirring and under astream of nitrogen, into the reactor containing the solution of MDI,while maintaining the temperature of the reaction medium at 50° C. byexternal heating.

The introduction of the SIL 700 solution lasts 1 h 30 and thetemperature of the reaction medium is maintained at 50° C. throughoutthe introduction.

After the introduction, the reaction medium is diluted with 350 g ofTHF, while maintaining the temperature at 50° C. The reaction leads tothe quantitative formation of a polysiloxane prepolymer containingα,ω-diisocyanate ends.

A solution of MEA obtained by dissolving 12.5 g of MEA in 70 g of THF isthen introduced (introduction time: 30 min) into the reactor containingthe above prepolymer, still with stirring, bubbling with nitrogen andmaintenance of the temperature at 50° C. The whole is then left to reactfor 7 h with stirring and at 50° C.

The end of the reaction may be monitored by checking, by infraredanalysis, the absence of —N═C═O absorption bands at 2270 cm⁻¹. Ifneeded, ethanol may also be added to the reaction medium in order toquench the reaction and totally consume the —N═C═O groups that are stillavailable; in this case, it is possible, for example, to add about 10 mlof ethanol and leave the whole to react for a further 4 h at 50° C.

At the end of the reaction, an organic (THF) solution of the desiredpolycondensate is obtained, which is then recovered and purified byprecipitation of the said solution in 5 l of an equi-volume (50/50)petroleum ether/ethyl ether mixture. The recovery yield is 93% by weightafter drying.

The acid number of the polycondensate obtained is 45.7 (theoretical:43).

Its number-average molecular weight is 12,600.

The polymer obtained is soluble in solvents such as dimethoxyethane,ethanol, isododecane and ethyl acetate.

EXAMPLE 4

Three examples of hair formulations are given here.

Hair Shaping Lotion

Polymer of Example 1 2 g Dimethoxyethane 50 g AMP 0.146 g Ethanol 40.67g Isododecane 7.18 g

This lotion is obtained by dissolving the polymer in the dimethoxyethaneand then adding the neutralizing agent, after which the solution isdiluted by adding ethanol and isododecane.

When applied to the hair after shampooing, this composition affords goodhold of the hairstyle and hair with very good sheen.

Hair Shaping Lotion

Polymer of Example 2 2 g Dimethoxyethane 50 g AMP 0.069 g Ethanol 43.14g Isododecane 4.80 g

This lotion is obtained by dissolving the polymer in the dimethoxyethaneand then adding the neutralizing agent, after which the solution isdiluted by adding ethanol and isododecane.

When applied to the hair after shampooing, this composition affords goodhold of the hairstyle and hair with very good sheen.

Hair Shaping Lotion

Polymer of Example 3 4.2 g Dimethoxyethane 47.66 g Ethanol 42.90 gIsododecane 4.76 g 2M HCl solution 0.476 g

This lotion is obtained by dissolving the polymer in thedimethoxyethane, followed by diluting the solution by adding ethanol andisododecane. The HCl solution is then added in order to neutralize thefinal solution.

When applied to the hair after shampooing, this composition affords goodhold of the hairstyle and hair with very good sheen.

EXAMPLE 5

Four examples of nail care bases are given here.

Nail Care Base

Polymer of Example 1 30 g Ethyl acetate 70 g

Nail Care Base

Polymer of Example 1 30 g Ethyl acetate 66.5 g Isododecane 3.5 g

Nail Care Base

Polymer of Example 2 30 g Ethyl acetate 70 g

Nail Care Base

Polymer of Example 2 30 g Ethyl acetate 66.5 g Isododecane 3.5 g

What is claimed is:
 1. A composition comprising at least one solution orat least one organic solvent-in-water emulsion, wherein said at leastone solution or at least one organic solvent-in-water emulsion comprisesat least one multiblock polycondensate dissolved in an aqueous solvent,an organic solvent, or a mixture thereof, the chain of said at least onemultiblock polycondensate comprising the repetition of at least onepolysiloxane block and at least one second block, wherein said at leastone second block is chosen from polyurethane and polyurea blocks,wherein said at least one second block comprises at least one ionizablegroup, wherein said at least one second block is chosen from at leastone polyurethane and/or polyurea block of formula (II) below:

wherein X², which may be identical or different, is —O— or —NH—, R is adivalent radical wherein said divalent radical is an aromatic, aliphaticor cycloaliphatic radical, x is an interger ranging from 1 to 10, and Bis chosen from radicals of formula (III):

 wherein R² is a linear or branched C₁-C₃ alkyl radical, Z is a —COOH or—SO₃H function or a salt of these acidic functions, and p and q, whichmay be identical or different, are integers ranging from 1 to 5, orformula (III′):

 wherein Z is a —COOH or —SO₃H function or a salt of these acidicfunctions, and further wherein the composition is a cosmetic ordermatological composition, and wherein the numerical ratio between saidat least one polyurethane and/or polyurea block and said at least onepolysiloxane block in the polycondensate ranges from 1:1 to 10:1.
 2. Acomposition according to claim 1 wherein said ratio ranges from 1:1 to3:1.
 3. A process for treating a keratin substance comprising applying acomposition comprising at least one solution or at least one organicsolvent-in-water emulsion to said substance, wherein said at least onesolution or at least one organic solvent-in-water emulsion comprises atleast one multiblock polycondensate dissolved in an aqueous solvent, anorganic solvent, or a mixture thereof, the chain of said at least onemultiblock polycondensate comprising the repetition of at least onepolysiloxane block and at least one second block, wherein if said atleast one second block is chosen from polyurethane and polyurea blocks,and further wherein said at least one second block comprises at leastone ionizable group.
 4. A process according to claim 3, wherein thenumber-average molecular weight of said polycondensate ranges from 2000to 500,000.
 5. A process according to claim 4, wherein said molecularweight ranges from 3000 to 250,000.
 6. A process according to claim 3,wherein the numerical ratio between said at least one polyurethaneand/or polyurea block and said at least one polysiloxane block in thepolycondensate ranges from 1:1 to 10:1.
 7. A process according to claim6, wherein said ratio ranges from 1:1 to 3:1.
 8. A process according toclaim 3, wherein said at least one ionizable group is a carboxylicfunction, a sulphonic function, or a combination of carboxylic andsulphonic functions, said carboxylic function, said sulphonic function,or said combination being in free or partially neutralized or totallyneutralized form.
 9. A process according to claim 3, wherein said atleast one ionizable group is a tertiary amine which is eithernon-neutralized or totally or partially neutralized or quaternized, or acombination thereof.
 10. A process according to claim 9, wherein thedegree of neutralization or of quaternization of said tertiary aminesranges from 0 to 100%.
 11. A process according to claim 10, wherein saiddegree ranges from 10 to 100%.
 12. A process according to claim 3,wherein said at least one polysiloxane block is of the formula (I)below:

wherein: P is a polysiloxane segment, X¹, which may be identical ordifferent, is —O— or —NH—, and R is a divalent radical wherein saiddivalent radical is an aromatic, aliphatic or cycloaliphatic radical.13. A process according to claim 12, wherein said polysiloxane segment Pis of the formula (I′) below:

wherein: the radicals R¹, which may be identical or different, arearomatic radicals or monovalent C₁-C₂₀ hydrocarbon radicals which arefree or substantially free of ethylenic unsaturations, Y represents adivalent hydrocarbon radical, and z is an integer such that the averagemolecular weight of the polysiloxane segment ranges from 300 to 10,000.14. A process according to claim 13, wherein said divalent hydrocarbonradical Y is an alkylene radical of formula —(CH₂)₃—, wherein arepresents an integer ranging/from 1 to
 10. 15. A process according toclaim 13, wherein said radicals R¹ are alkyl radicals, cycloalkylradicals, aryl radicals, or arylalkyl radicals.
 16. A process accordingto claim 15, wherein said alkyl radicals are methyl, ethyl, propyl,isopropyl, butyl, pentyl, hexyl, octyl, decyl, dodecyl or octadecylradicals.
 17. A process according to claim 15, wherein said cycloalkylradicals are cyclohexyl radicals.
 18. A process according to claim 15,wherein said aryl radicals are phenyl, naphthyl, tolyl or xylylradicals.
 19. A process according to claim 15, wherein said arylalkylradicals are benzyl and phenylethyl radicals.
 20. A process according toclaim 12, wherein said polysiloxane segment P is of the formula (I″)below:

wherein a represents an integer ranging from 1 to 10, and z representsan integer such that the average molecular weight of the polysiloxanesegment ranges from 300 to 10,000.
 21. A process according to claim 3,wherein said at least one polyurethane and/or polyurea block is of theformula (II) below:

wherein: X², which may be identical or different, is —O— or —NH—, R is adivalent radical wherein said divalent radical is an aromatic, aliphaticor cycloaliphatic radical, x is an integer ranging from 1 to 10, and Bis a divalent hydrocarbon radical bearing a positive or negative ioniccharge.
 22. A process according to claim 21, wherein x ranges from 1 to3.
 23. A process according to claim 21, wherein said radical B bears agroup having at least one carboxylic function, at least one sulphonicfunction or a combination of carboxylic and sulphonic functions, whereinsaid at least one carboxylic function, said at least one sulphonicfunction or said combination is in free form or alternatively partiallyor totally neutralized with an inorganic or organic base.
 24. A processaccording to claim 23, wherein said radical B is of the formula (III)below:

wherein R² is a linear or branched C₁-C₃ alkyl radical, Z is a —COOH or—SO₃H function or a salt of these acidic functions, and p and q, whichmay be identical or different, are integers ranging from 1 to
 5. 25. Aprocess according to claim 23, wherein said radical B is of the formula(III′) below:

wherein Z is a —COOH or —SO₃H function or a salt of these acidicfunctions.
 26. A process according to claim 21, wherein said radical Bbears tertiary amine groups, and further wherein said tertiary aminegroups are either non-neutralized or partially or totally neutralizedwith an inorganic or organic base, or quaternized.
 27. A processaccording to claim 26, wherein said radical B is of the formula (IV)below:

wherein R³ is a linear or branched C₁-C₄ alkyl radical, and r and s,which may be identical or different, are both integers which range from1 to
 10. 28. A process according to claim 27, wherein the radical B, inneutralized or quaternized form, is of the formula (IV′):

wherein R³ is as defined in claim 27, and R⁴ is either hydrogen or alinear or branched C₁-C₁₀ alkyl radical or an aromatic ring.
 29. Aprocess according to claim 12, wherein said radical R is a radical ofthe following formulae:

wherein b is an integer ranging from 0 to 3, and c is an integer rangingfrom 1 to
 20. 30. A process according to claim 29, wherein c ranges from2 to
 12. 31. A process according to claim 29, wherein said radical R ishexamethylene, 4,4′-biphenylenemethane, 2,4-tolylene, 2,6-tolylene,1,5-naphthylene, p-phenylene, methylene4,4-bis-cyclohexyl or thedivalent radical derived from isophorone.
 32. A process according toclaim 3, wherein said polycondensate is obtained according to a processcomprising the steps of (A) in a first step, reacting a polysiloxanepolymer of α,ω-dihydroxypolysiloxane, α,ω-diaminopolysiloxane,α,ω-aminohydroxy- or hydroxyamino-polysiloxane type, and a diisocyanate,wherein said diisocyanate is present in stoichiometric amount or instoichiometric excess and further wherein a polysiloxane is obtainedhaving an isocyanate function at each of its chain ends; (B) in a secondstep, coupling the chains of the polysiloxane obtained in said firststep by reaction with a coupler wherein said coupler is a diol, daimine,or aminoalcohol, and further wherein said coupler bears cationizable oranionizable groups; and (C) in a third step, optionally partially ortotally ionizing the cationizable or anionizable groups of thepolycondensate obtained after the second step, and dissolving thepolycondensate in an aqueous, organic or aqueous-organic solvent system.33. A process according to claim 32, wherein the degree of ionization insaid third step ranges from 0 to 100%.
 34. A process according to claim33, wherein said degree of ionization ranges from 10 to 100%.
 35. Aprocess according to claim 32, wherein the starting polysiloxane polymerin said first step is of the formula: X³—P—X³ wherein P is apolysiloxane segment, and X³, which can be identical or different, is—OH or —NH₂.
 36. A process according to claim 32, wherein saiddiisocyanate is of the formula: O═C═N—R—N═C═O wherein R is a divalentradical chosen from aromatic, aliphatic and cycloaliphatic radicals. 37.A process according to claim 32, wherein said coupler is of the formula:X⁴—B—X⁴ wherein B is a divalent hydrocarbon radical bearing a positiveor negative ionic charge, and X⁴ is —OH or —NH₂.
 38. A process accordingto claim 3, wherein said solvent system comprises at least one organicsolvent chosen from acetone, methyl ethyl ketone, methyl acetate, butylacetate, ethyl acetate, isopropanol, ethanol, dimethoxyethane,diethoxyethane, ethylene glycol and propylene glycol esters, ethyleneglycol and propylene glycol ethers, ethylene glycol, and propyleneglycol ester ethers.
 39. A process according to claim 38, wherein saidat least one organic solvent is miscible with water.
 40. A processaccording to claim 3 wherein said solvent system contains at least oneorganic solvent which is immiscible in water.
 41. A process according toclaim 3, wherein said solvent system contains at least one globalsolvent for the polycondensate and at least one additional solvent whichis less polar than said global solvent.
 42. A process according to claim41, wherein said at least one additional solvent dissolves thepolysiloxane blocks of the polycondensate and has a slower rate ofevaporation than said global solvent.
 43. A process according to claim41, wherein said at least one global solvent is acetone, methyl ethylketone, methyl acetate, butyl acetate, ethyl acetate, isopropanol,ethanol, dimethoxyethane, diethoxyethane, ethylene glycol or propyleneglycol esters, ethylene glycol or propylene glycol ethers, or ethyleneglycol or propylene glycol ester ethers or a mixture thereof.
 44. Aprocess according to claim 41, wherein said at least one additionalsolvent is a cyclic silicone, a hydrocarbon, or a mixture thereof.
 45. Aprocess according to claim 3, wherein said composition is a haircomposition.
 46. A process according to claim 3, wherein saidcomposition is a make-up composition.
 47. A process according to claim3, wherein said composition is a nail varnish or a nail care base.
 48. Aprocess according to claim 3, wherein said composition is a mascara. 49.A process according to claim 3, wherein said composition is a skincarecomposition.
 50. A process according to claim 3, wherein saidcomposition is an antisun composition.
 51. A composition comprising atleast one solution or at least one organic solvent-in-water emulsion,wherein said at least one solution or at least one organicsolvent-in-water emulsion comprises at least one multiblockpolycondensate dissolved in an aqueous solvent, an organic solvent, or amixture thereof, the chain of said at least one multiblockpolycondensate comprising the repetition of at least one polysiloxaneblock and at least one second block, wherein said at least one secondblock is chosen from polyurethane and polyurea blocks, wherein said atleast one second block comprises at least one ionizable group, whereinsaid at least one second block is chosen from at least one polyurethaneand/or polyurea block of formula (II) below:

wherein X², which may be identical or different, is —O— or —NH—, R is adivalent radical wherein said divalent radical is an aromatic, aliphaticor cycloaliphatic radical, x is an interger ranging from 1 to 10, and Bis chosen from radicals of formula (III):

 wherein R² is a linear or branched C₁-C₃ alkyl radical, Z is a —COOH or—SO₃H function or a salt of these acidic functions, and p and q, whichmay be identical or different, are integers ranging from 1 to 5, orformula (III′):

 wherein Z is a —COOH or —SO₃H function or a salt of these acidicfunctions, and further wherein the composition is a cosmetic ordermatological composition, and wherein the composition contains atleast one organic solvent which is immiscible in water.
 52. Acomposition comprising at least one solution or at least one organicsolvent-in-water emulsion, wherein said at least one solution or atleast one organic solvent-in-water emulsion comprises at least onemultiblock polycondensate dissolved in an aqueous solvent, an organicsolvent, or a mixture thereof, the chain of said at least one multiblockpolycondensate comprising the repetition of at least one polysiloxaneblock and at least one second block, wherein said at least one secondblock is chosen from polyurethane and polyurea blocks, wherein said atleast one second block comprises at least one ionizable group, whereinsaid at least one second block is chosen from at least one polyurethaneand/or polyurea block of formula (II) below:

wherein X², which may be identical or different, is —O— or —NH—, R is adivalent radical wherein said divalent radical is an aromatic, aliphaticor cycloaliphatic radical, x is an interger ranging from 1 to 10, and Bis chosen from radicals of formula (III):

 wherein R² is a linear or branched C₁-C₃ alkyl radical, Z is a —COOH or—SO₃H function or a salt of these acidic functions, and p and q, whichmay be identical or different, are integers ranging from 1 to 5, orformula (III′):

 wherein Z is a —COOH or —SO₃H function or a salt of these acidicfunctions, and further wherein the composition is a cosmetic ordermatological composition, wherein the composition contains at leastone global solvent for the polycondensate and at least one additionalsolvent which is less polar than said global solvent, and wherein saidat least one additional solvent dissolves the polysiloxane blocks of thepolycondensate and has a slower rate of evaporation than said globalsolvent.
 53. A composition comprising at least one solution or at leastone organic solvent-in-water emulsion, wherein said at least onesolution or at least one organic solvent-in-water emulsion comprises atleast one multiblock polycondensate dissolved in an aqueous solvent, anorganic solvent, or a mixture thereof, the chain of said at least onemultiblock polycondensate comprising the repetition of at least onepolysiloxane block and at least one second block, wherein said at leastone second block is chosen from polyurethane and polyurea blocks,wherein said at least one second block comprises at least one ionizablegroup, wherein said at least one second block is chosen from at leastone polyurethane and/or polyurea block of formula (II) below:

wherein X², which may be identical or different, is —O— or —NH—, R is adivalent radical wherein said divalent radical is an aromatic, aliphaticor cycloaliphatic radical, x is an interger ranging from 1 to 10, and Bis chosen from radicals of formula (III):

 wherein R² is a linear or branched C₁-C₃ alkyl radical, Z is a —COOH or—SO₃H function or a salt of these acidic functions, and p and q, whichmay be identical or different, are integers ranging from 1 to 5, orformula (III′):

 wherein Z is a —COOH or —SO₃H function or a salt of these acidicfunctions, and further wherein the composition is a cosmetic ordermatological composition, wherein the composition contains at leastone global solvent for the polycondensate and at least one additionalsolvent which is less polar than said global solvent, and wherein saidat least one additional solvent is selected from cyclic silicones andhydrocarbons.
 54. A process for preparing a cosmetic composition, saidprocess comprising adding at least one polycondensate solution oremulsion as a film-forming agent or as an additive for a film-formingagent, to the composition, wherein said at least one polycondensatesolution or emulsion comprises at least one solution or at least oneorganic solvent-in-water emulsion, wherein said at least one solution orat least one organic solvent-in-water emulsion comprises at least onemultiblock polycondensate dissolved in an aqueous solvent, an organicsolvent, or a mixture thereof, the chain of said at least one multiblockpolycondensate comprising the repetition of at least one polysiloxaneblock and at least one second block, wherein said at least one secondblock is chosen from polyurethane and polyurea blocks, wherein said atleast one second block comprises at least one ionizable group, whereinsaid at least one second block is chosen from at least one polyurethaneand/or polyurea block of formula (II) below:

wherein X², which may be identical or different, is —O— or —NH—, R is adivalent radical wherein said divalent radical is an aromatic, aliphaticor cycloaliphatic radical, x is an interger ranging from 1 to 10, and Bis chosen from radicals of formula (III):

 wherein R² is a linear or branched C₁-C₃ alkyl radical, Z is a —COOH or—SO₃H function or a salt of these acidic functions, and p and q, whichmay be identical or different, are integers ranging from 1 to 5, orformula (III′):

 wherein Z is a —COOH or —SO₃H function or a salt of these acidicfunctions, and further wherein the composition is a cosmetic ordermatological composition.